对桥的分析和诊断测试

资料简介：

　　Analysis and diagnostic testing of a bridgeAbstract
　　The paper deals with analytical and experimental study to determine the cause of transverse crack patterns on two parallel seven-span launched steel-girder bridges. Major cracks are concentrated between the beginning and the middle of the third span. The crack patterns are symmetric with respect to the fourth span and can be found on both bridges. Diagnostic tests were performed with crawling-speed and high-speed trucks. The measured distribution factors are consistently more uniform than code-specified values and the impact factors are smaller than specified values. Tests on concrete cores indicated that the water/cement ratio is higher than code specified ratio and that the strength of concrete is greater than specified. Three-dimensional finite-element analysis indicated that stresses in the slab due to live load do not match with existing crack patterns. However, the analysis of the concrete pouring sequence showed that maximum concrete stresses are large and the locations correspond to those of the most severe slab cracking. Therefore, it is concluded that the bridge deck slab cracks resulted primarily from the deck pouring sequence, combined with concrete shrinkage. Since the primary causes of cracks are not active anymore, an epoxy injection method has been recommended to seal cracks.
　　7 2000 Elsevier Science Ltd. All rights reserved.
　　对桥的分析和诊断测试
　　摘要
　　这篇论文对分析与实验研究进行论述，以确定两个平行的7大跨度钢加腋梁桥的横向裂缝模式产生的原因。裂缝主要集中在开始和第三大跨度中部之间的位置。裂缝关于第四跨度对称，而且在两座桥上都可找到。诊断试验由低速和高速卡车完成。测定的分布系数一贯比代码中指定的值更加平均，影响因素比指定的值要小。混凝土核心试验表明，水／水泥比例较代码指定比例更高，且混凝土强度比指定的大。三维有限元分析表明活荷载板上的应力与现有的裂缝模式不相匹配。然而，混凝土的浇筑序列分析表明最大的混凝土应力很大，位置对应于最严重的板开裂的。因此，可以得出结论该桥桥面板裂缝主要是由甲板浇筑序列和混凝土的收缩引起的。由于裂缝的主要成因不再活跃了，可以将环氧树脂注射方法应用到裂痕研究中。